Alloy



Patented Aug. is, 1938 k ,PATE

NT OFFICE ALLOY Anthony G. de Golyer, New York, N. Y.

No Drawing.

3 Claims.

The present invention relates to a new and useful alloy and relatesparticularly to an alloy containing boron, tungsten; chromium, vanadium,zirconium and nickel, which is character 5 ized by being responsive tothermal treatment for'the improvement of physical properties.

Y An object of the present invention is to provide an alloy especiallyadapted for use as metal cutting tools; the cutting eiiiciency of whichis superior to that of present known high speed steels and other alloys.A further object is provide an alloy which is free from, orsubstantially free from carbon and which isreadil-y amenable to thermaltreatment, by means of which the hardness, tensile strength, cutting ef-I ficiency and other physical properties and characteristics may beaccurately controlled over a comparatively wide range.

. I have found through experiment that byalloying or otherwiseintimately combining boron, tungsten, vanadium, chromium, zirconium andnickel within the range of boron 0.50% to 3%,

tungsten 5% to 30%, vanadium 1% to 8%, zir-.

'conium 0.25% to 5%,.chromium 1% to and 25 nickel substantially thebalance, I obtain metallic compositions which poses in combinationmaterially improved physical properties compared to those of heretoforeknown alloys or compositions intended for the cutting or working ofmetals.

Alloys of this invention may be used in the cast condition butapproximate maximum values of hardness, resistance to impact and certainother important physical properties can, be developed 5 only throughthermal treatment, or through mechanical working and subsequent thermaltreatment. Bodies of the alloys which havebeen subjected to suchtreatment are particularly valuable for use as tools, dies and the likefor the 40 cutting or mechanical working of metals. Numerous metalliccompositions have heretofore been proposed as improvement on thegenerally known 18-4-1 type of tungsten-chromiumvanadium high speedtoolsteel, and while many such compositions possess greater hardnessthansuch steel, all of them have disadvantages which render themunsuitable for general application as metal cutting or forming tools.Compositions containing principally carbides of tungsten, mol'ybdenum ortantalum bonded: with a relatively soft matrix metal have a high degreeof hard:

ness, but are extremely brittle. Cast compositions of-thetypesheretofore proposed requirethe presence of at least 1.50% carbon toqualify 4 u as metal cutting tools and, as is well" known, suchApplication September 3, 1936, Serial No. 99,243

alloys are not only brittle, but are so sensitive to variousoperatingconditions as to greatly restrict the scope of usefulness. Oneof the greatest disadvantages of such heretofore proposed compositionsis that none of them 'are responsive to thermal treatment for regulationof physical properties, and consequently physical properties andcharacteristics are governed entirelyby the chemical composition of thesintered or cast material.

My alloy may be used in the as-cast condition, or it may be forged orotherwise mechanically worked. In either case I prefer to subject thealloy to thermal treatmentbefore using it as a cutting tool or die. Boththe cast and forged material are equally amenable to thermal treatment.For example, cast bodies of this alloy may have a hardness of from-50 toon the Rockwell C. scaleand by subjecting thematerial to suitablethermal treatment, such as quenching from 0 ly 60 to Rockwell C. In thelatter condition the alloy is especially valuable for the cutting ormechanical working of a large number of metals and alloys, as well asnumerous non-metallic vis that virtually all of the maximum hardness,developed by thermal treatment, is retained when the alloy is subjectedto elevated temperatures, e. g. such as are generated in the tip ofstool cutting metal at high speed. Although the alloy has a high degreeof hardness and resistance to abrasion by hot metal chips, especiallyafter thermal treatment, it is remarkably resistant to failure fromsudden or repeated shock. Therefore. tools made of the present alloyretain an emcient cutting edge for longer periods than other tools. Themore important distinctive and valuable advantages are, apparently, dueto the presence of appreciable amounts of boron in the composition, inconjunction with the otheressential component elements within thepercentages specified herein.

I have found that molybdenum may be used to supplant all or a portion ofthe tungsten oi the materials. An important property of this alloy 319.5%. Vanadium 4%, chromium 4%, zirconium 0.80%, nickel balance; boron1.65%, molybdenum.

l3%, vanadium 3.5%, chromium 3.5%, zirconium 3.75%, nickel balance;boron 1.70% tungsten 5% molybdenum vanadium 5%, chromium 8%, zirconium4.6%, nickel balance; boron 1.10%, molybdenum 12%, vanadium 6%, chromium7%, zirconium 1.75%, nickel balance.

An objective of the present invention is to provide alloys having highhardness, high resistance to shock and impact, advantageous metalcutting properties, etc., which are free or substantially free fromcarbon, and thus eliminate all of the serious disadvantages associatedwith carbon containing non-ferrous alloys or compositions intended formetal cutting tools. Although I prefer to have the alloys of thisinvention entirely free from carbon, in many instances I have foundcarbon present in the nature of an impurity incidental to manufacture.It is important to restrict the amount of carbon so present to a maximumof about 0.15%, as I have found that the presence or higher percentagesof this element make the alloy extremely brittle and subject to failureduring cutting operations, and, greatly retards or entirely prevents thedesired and necessary reactions during thermal treatment. Furthermore,the presence of appreciable amounts of carbon decreases the red hardnessof the alloy, i. e. hardness at temperaturm of approximately 550 C. andhigher.

By reason of the iact that the elements forming the essential componentsof the alloy of the present invention invariably are contaminated withother elements whenproduced in commercial quantities, the alloys of myinvention usually contain insignificant amounts of one or more elementsin the nature of impurities incidental to manufacture. Because of thefact that the maximum values of physical properties of thepresent alloycan be developed only through thermal treatment, it is essential thatthe amount of such incidental impurities present be limited topercentages which will not be efiective in retarding, or entirelypreventing the necessary physical reactions during thermal treatment.the percentages of such impurities should also be restricted to amountswhich will not be eiiective on the physical properties orcharacteristics of the alloy either before or after.

thermal treatment.

I have found that the most harmful impurities commonly present, inaddition to carbon, are silicon and aluminum. The presence of either of.these elements in amounts greater than approximately 1% renders thealloyoi the present invention entirely unsuitable for thermaltreatcomponents tungsten mium 1% to 25%, the

ment bymeans of which the hardness, tensile strength and impactresistance and other properties may be accurately controlled. One of thechief disadvantagesoi silicon and aluminum is that these elementsapparently form chemical compounds with one or more or the essential ofthe present alloy,'and such compounds are not only hard, impactresistance, but are virtually insoluble in the solid composition duringthermal treatment.

' It will be apparent, therefore, that the presence of eifective amountsof impurities, such as carbon, silicon and aluminum, materially changethe character of the alloy through rendering it not amenable to thermaltreatment.

My investigations indicate that the preferred structure of a body of thepresent alloy is produced only by means of thermal treatment, 'and thatthis comprises at least two principal constituents: one, a relativelyhard intermetallic compound of boron with one or more of the otheressential components; and, second, a solid solution of two or more ofthe essential components which has a lower degree of hardness andfunctions as a matrix. In some instances the structure will contain athird constituent in the nature of an eutectoid. The ratio of theconstituents and the ratio of particle size in any particular body ofthe alloy may be accurately controlled and fixed .over a wide range bymeans of thermal treatment, or mechanical working and subsequent thermaltreatment.

By reason of the combined advantageous physical properties possessed bythe alloy of the present invention, tools andother articles composed ofthis alloy may be operated efllciently and economically under conditionswhich are impossible or uneconomical with tools or articles composed ofheretofore known alloys or metallic compositions.

By the term the balance substantially nickel in the foregoing and in thefollowing claims, I intend that the alloy of the present inventionbrittle and lacking in.

comprises boron, vanadium, zirconium, chromium and metal of the grouptungsten, molybdenum and uranium, within the percentage limitsspecifled, with the remainder nickel except for ineffective amounts ofimpurities which may be present incidental to manufacture, ashereinbefore explained.

I claim:

1. A precipitation hardened alloy containing boron 0.50% to 3%, metalfrom the group tungsten, molybdenum and uranium 5% to 30%, vanadium 1%to 8%, zirconium 0.25% to 5%, chromium 1% to 25%, the balance'nickel.

2. A precipitation hardened alloy containing boron 0.50% to 3%, tungsten5% to 30%, vanadium 1% to 8%, zirconium 0.25% to 5%, chromium 1% to 25%,the balance nickel.

3. A precipitation hardenedj alloy containing boron 0.50% to 3%.molybdenum 5% to 30%, vanadium 1% to 8%, zirconium 0.25% to 5%,chrobalance nickel.

ANTHONY G. D! GOLYER. 65

